First, we should pay attention to the power matching problem.

Theoretically, the rated power of the speaker should be equal to the rated output power of the power amplifier before the equipment can work normally. It is recommended to pull the cart instead of the pony. If conditions permit, you can choose a high-power amplifier instead of a low-power amplifier.

Generally speaking, the rated output power of the power amplifier is at least 2 times higher than that of the speaker. Although the big horse-drawn car will cause unnecessary waste to the success rate, the small horse-drawn car will make the speaker not get enough driving force, and the whole sound system will not play the best sound effect.

Second, impedance matching.

The output of the amplifier and the input impedance of the speaker should also be the same. Although there are some slight deviations between them, which have little influence on the sound quality, they will only affect the output power of the power amplifier. However, it must be reminded that if the input impedance of the speaker is much lower than the output impedance of the power amplifier, the distortion will increase obviously, and the power amplifier will be damaged in serious cases. So try to choose the same one.

Finally, the matching problem of damping coefficient is discussed.

The so-called damping is the loudspeaker damping to measure the internal resistance of the output stage of the power amplifier. If the damping coefficient is too high, the sound emitted by the speaker will be dry and round; If the damping coefficient is too low, the sound is likely to stick together. Therefore, when configuring the power amplifier, it should be noted that the damping coefficient of the stone machine is controlled between 30 and 40, while the internal resistance of the courage machine is high, so it should not exceed 10.

Extended data

Basic components of power amplifier:

Power amplifier usually consists of three parts: preamplifier and driver amplifier.

1, and the preamplifier plays a matching role. Its input impedance is high (not less than10kΩ), which can absorb most front-end signals, and its output impedance is low (less than several tens Ω), which can transmit most signal wind. At the same time, it is also a current amplifier, which converts the input voltage signal into a current signal and amplifies it appropriately.

2. Drive the amplifier as a bridge. It further amplifies the current signal sent by the preamplifier into a medium power signal, which drives the final power amplifier to work normally. If the power amplifier is not driven, it is impossible for the final power amplifier to send out high-power sound signals.

3. The final power amplifier plays a key role. It will drive the current signal from the amplifier to form a high-power signal and drive the speaker to make sound. Its technical index determines the technical index of the whole power amplifier.

Baidu encyclopedia-power amplifier

How to choose power amplifier and speaker for self-made audio

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1.

Power amplifier selection: Power amplifier is mainly selection.

A speaker with rated output power of 100W*2 impedance and 8 ohms can basically meet the rated power of 50W-80W(8 ohms). The power amplifier is twice as powerful as the speaker, with higher power and lower distortion. )

Choose a large-size transformer (diameter 13 cm or more) and a filter capacitor above 20000 microfarads, and the high power is basically guaranteed; It is best to use Toshiba (Sweet Warm Tone) and Sanken (Leng Yan Strong Tone) high-power tubes for the back stage tube, and it is best to have a horn protection circuit (with two relays). It doesn't matter whether it is a famous brand or not, because famous brands are more expensive. As long as the above items are good components, the sound and power can be basically guaranteed. )

If you are an audiophile and want the best sound quality, you can choose a class A amplifier which is several times more expensive, and that sound can be the same as.

Electron tube power amplifier is comparable, and the overall performance is much higher than that of electron tube power amplifier (electron tube is an old technology decades ago, not as advanced as transistor technology).

2. Speaker selection: it must be a well-known brand! Because there are basically no parameters for brand speakers, we don't know the frequency range. There are many famous brand speakers in China: Silver Flute, Blue Whale, Le Fei, Suowei and hivi. . They are all first-class speakers, so choose a speaker with an impedance of 8 ohms to match the power amplifier (a 5 ohm speaker is louder than an 8 ohm speaker, but almost as big as a 4 ohm speaker, so don't think it's good to be big, that's the impedance factor, the impedance is small and the output sound is big); It is better to choose a lower parameter F0 (lowest resonance frequency).

Good horn size is not big, but subwoofer parameters are good. 6, 8 inches as long as there are 38, 35HZ subwoofers, 10, 12 inches have 30, 25HZ subwoofer parameters to choose from. (The horn power should be below 100W, because the horn power is large, so the power amplifier needs to be larger than the horn power, and the sound is good; The price ratio of power amplifier 200W*2 is 100W*2.

The power amplifier is twice as expensive, and the speaker power is high, which is basically a waste of resources)

3. Speaker production: There is a great relationship between the size of the speaker and the speaker. The bigger the speaker, the louder the volume of the speaker (Baidu knows about the size of the speaker, you can search it). If there is not enough speaker space, the speaker will not have the lowest resonance frequency! Because the lowest sound is the spatial resonance between the speakers, not the speakers themselves-

You put a bare speaker on the table, without which you can hardly hear the bass.

(It's not that the speaker doesn't have bass, it's that there is no sound box to make it emit ultra-bass-baffle principle)

How to choose and match audio and power amplifier?

For ordinary households, those strict professional and technical requirements can be ignored. Good results can be achieved by considering only a few major issues:

1, speaker, or speaker, its rated power is greater than the output power of the power amplifier, and consider increasing the speaker capacity appropriately, leaving a certain reserve margin;

2. The output and input impedances of the two devices are matched. If the output impedance of the amplifier is 8 Ω, the input impedance of the speaker should also be 8 Ω. That is, the impedance matching between the two can make the speaker get the maximum output power and play its role. When the impedance is not matched, the amplifier cannot output the maximum signal power;

3. The audio signal connection between them. If it is a low power device, you can use thicker common copper core multi-strand wire; However, for high-power equipment, special audio lines are needed to reduce line loss and influence on audio signals;

4. Selection of power amplifier equipment and speakers. If you build a home theater, you can give priority to the surround sound 5. 1 or 7. 1 speaker series products of big brands, and the specifications and characteristics are guaranteed, which can avoid the blindness of users. In addition to high-fidelity types, brand is also an important quality factor of power amplifier equipment. When choosing, we should not only consider the performance, function and power index, but also consider whether the audio output interface can meet the connection problem of the speaker system.

5. Ordinary two-speaker stereo system can satisfy 1 and 2. Usually when buying an amplifier, the store will give away an audio cable, but the quality of the cable is relatively ordinary.